Military knives and bayonets are customary weapons of ground combat forces. A bayonet is usually an elongated weapon that can be fixed to the end of the barrel of a rifle. Conventional bayonets are shown and described in U.S. Pat. No. 4,821,356, issued Apr. 18, 1989, whose entire disclosure is herein incorporated by reference.
Survival knives and bayonets have been adapted to perform multiple functions. For example, many are equipped with a shearing blade that cooperates with a scabbard lug to provide wire or fabric cutters. It is also conventional to use an extension rod enclosed in a hollow handle for securing the blade to the handle. In this connection, the extension rod threads onto the tang of the bayonet or knife blade and extends toward the butt of the handle. At the handle butt, either a butt or a mounting latch for the bayonet has a receiver hole that coincides with the end of the extension rod. A suitable nut threads through the butt or the latches to secure the butt or the latches to the extension rod. In this manner, the extension rod is compressed and the blade is securely mounted to the handle.
One of the drawbacks of conventional bayonets and survival knives is that they provide no means for protecting the user from cutting into an electrified wire. It is known that defensive emplacements that include barbed wire fences and chain link fences often electrify those fences. A fence may be electrified to either shock an intruder with high voltage or detect an intruder by monitoring the resistance of the electrified fence which changes as a fence is climbed or tampered with. Thus, a wire represents two hazards to the combatant: a physical obstacle that inhibits motion and can cause cuts and bruises as well as applying an electrical shock to the soldier or alerting the security personnel of the soldier's attempt to bypass the fence. In conventional knives and bayonets, a metal extension rod connects the tang of the blade to the handle. If the wire is electrified, the metal extension rod carries the current to the far or distal end of the handle of the knife or bayonet. If that end is metal, the user of the knife or bayonet will receive an electric shock.
Alternatively, the owner of an electrified fence has a need for a bayonet or survival knife that indicates whether or not the fence is electrified. For example, a rancher who uses an electrified fence to contain animals such as cows or horses commonly uses a knife such as a survival knife while working in the field. A lack of current in the fence indicates that the fence needs repair. Therefore such a rancher needs a combination knife and voltage indicator that would allow the rancher to determine if his or her fence is electrified while he or she is in the field.